The site's users were up to 955 million, with 552 million active daily visitors.

Investors were not impressed, however, and after a brief rise its shares fell to record lows.

Slowing growth in its advertising revenues, which reached $992m (up from $776m a year ago), worried some.

David Wain-Heapy, operations director for social media specialists, Best Response Social, said Facebook needed a stronger mobile strategy.

"Satisfactory numbers from the social networking giant, but nothing special. The jury is still out on whether Facebook can be sufficiently monetised to justify its insane valuation," he said.

"Facebook urgently needs to figure out how its advertisers can best monetise its user base, and that's the great unknown.

"Just how are people willing to spend money when they are socialising online? This is the billion dollar question to which nobody yet has an answer."

Analysts also pointed to weaknesses in the average revenue Facebook makes per user - $1.21 in the first quarter, down 6% over a year ago.

Others appeared spooked by the big losses suffered by partners Zyng, whose games including FarmVille are said to represent 15% of Facebook's revenue but which made a loss of $108m in the first half of 2012.

Shares in Zynga fell by about 3.6% in after-hours trading, down to $3.06 from its IPO price of $10.

"Our goal is to help every person stay connected and every product they use be a great social experience," said Mark Zuckerberg, Facebook founder and CEO. "That's why we're so focused on investing in our priorities of mobile, platform and social ads to help people have these experiences with their friends."